1. Field of the Invention
The present invention relates to an assembly antenna array, particularly to an integration antenna array, wherein several antenna arrays share a common ground plate.
2. Description of the Related Art
An antenna array is an antenna system consisting of a plurality of identical antennae, such as symmetrical antennae, arranged according to a special rule. A single antenna is hard to control its radiation pattern and hard to have sufficient gain. Further, the important parameters of a single antenna are less likely to meet a high-standard application. Therefore, some products needing high transmission quality have to adopt antenna arrays. In an antenna array, the component antenna units are arranged according to a special rule and have a special signal feeding method to attain the required effect. The more the antenna units of an antenna array, the higher the gain, and the larger the size.
In a conventional antenna array, radiation conductors of identical antennae are parallel arranged into an arrayed structure, and the spacing therebetween is 0.5-0.9 wavelength of the wireless signal. When looked top down, the radiation energy of an antenna array exhibits an 8-shape distribution. On two planes respectively parallel and vertical to the antenna radiation conductors, a user receives two signals from the antennae at the same time, wherein the phases of the two signals are identical, and the transmission distances of the two signals are the longest. When the two signals of identical phases are combined, the intensity of the combined signals is double the intensity of a single signal. In other words, the gain increases by 3 dB.
In the conventional design of antenna arrays, there are mainly two methods to form a dipole antenna array having dual polarizations. One method thereof is exemplified by a U.S. Pat. No. 5,923,296 “Dual Polarized Microstrip Patch Antenna Array for PCS Base Stations” shown in FIG. 1, wherein a set of copper patches 3 and a set of copper patches 5 are alternately arranged on a printed circuit board 1 to form two antenna arrays polarized vertically to each other. However, the volume of such a design doubles that of the ordinary antenna array. Besides, the two antenna structures are asymmetric. Thus, the radiation patterns thereof have a great difference, and interference is likely to occur therebetween.
Another method is exemplified by a U.S. Pat. No. 6,985,123 “Dual-Polarization Antenna Array” shown in FIG. 2, wherein a single set of antenna elements 15′ cooperates with two sets of mutually-vertical feed-in signals 13′ to generate two sets of mutually-vertical antenna array signals in a same radiation conductor structure. However, such a design needs a very complicated network of feed-in transmission cables. Thus, the signal will greatly attenuate, and interference between the transmission cables increases. Besides, the antenna structure is hard to fabricate and thus has a high fabrication cost and a low yield. Further, as two sets of antenna array signals are excited on the surface of the same radiation structure, the interference between antennae is very obvious.
To overcome the conventional problems, the present invention proposes an assembly antenna array, which adopts the arrayed radiation conductors arranged vertically to greatly reduce the size of the antenna structure, and which uses the transmission members arranged on different surfaces of the ground plate to feed signals into the network, whereby the complexity of the antenna structure is greatly reduced, and whereby the ground plate blocks the interference between the transmission members, wherefore the present invention has the minimum loss and the best radiation transmission efficiency.